1235825 (1) 玖、發明說明 【發明所屬之技術領域】 本發明是關於主要在半導體製造設備或化學工廠所使 用的壓力感應器及壓力控制裝置以及壓力式流量控制裝置 者，特別是在測量流體的壓力之壓力感應器的輸出隨著時 間變化的情況，當該變化量（漂移量）超過預定的設定値 時，藉由自動地進行壓力感應器零點修正，可防止因壓力 檢測値之隨著時間變化所引起的壓力或流量的測定誤差之 產生的壓力感應器及壓力控制裝置以及壓力式流量控制裝 置的自動零點修正裝置。 【先前技術】 在半導體製造設備或化學製造設備等，被要求以高精 度控制各種原料的供給流量或供給壓力等，爲了對應這些 的要求，而開發了各種型式的壓力控制裝置或流量控制裝 置以及使用於此之壓力感應器。 第1 3及1 4圖是顯示以往的流量控制裝置的一例者，在 第13圖（US專利第5 1 4694 1號），藉由將孔口 F的上游側 氣體壓P!、孔口側F的入口側與喉部間的差壓△ p輸入至 運算手段C，根據以該運算手段C所算出的流量Wg與設 定流量Wr，經由閥控制器VC開關控制控制閥V，來將孔 口下游側的氣體流量控制於設定流量之所謂左壓式流量控 制裝置爲眾所皆知。 同樣地，第1 4圖（日本特開平8 - 3 3 8 5 4 6號）是顯示以 (2) 1235825 往的壓力式流重控制裝置的一*例者’錯由在臨界條件下以 孔口下游側的氣體流量作爲Qc = KPi (其中P!爲孔口上游 俱ij壓力）以運算手段來運算，於設定流量Qs與前述運算 流量Qc的差變小之方向開關控制控制閥v ’來將孔口 F 的下游側之氣體流1量控制於設定値’作爲在臨1界條件下（ p2/Pi ^大約0.5 )所使用的壓力式流量控制裝置爲眾所皆 知。 再者，在如上述之流量控制裝置等，均須要檢測孔口 F的上游側之氣體壓p 1等，爲了進行這些壓力檢測’多數 利用使用應變計等的半導體壓感元件之壓力感應器。 【專利文獻1】美國專利第5 1 4694 1號公報 【專利文獻2】日本特開平8-33 8546號公報 檢測前述流體壓力P 1的壓力感應器是根據感應器周 圍的環境條件例如氣體溫度等，可得知其輸出値變動。即 ，即使配置於相同流體壓力內的壓力感應器，受到流體溫 度變動，壓力感應器的輸出値也變動。 例如，在前述應變計型壓力感應器，壓力變化成電壓 ，形成：當將橫軸取爲壓力時縱軸對應於輸出電壓之關係 。又，作爲輸出特性，期望爲：絕對壓力爲零時’輸出電 壓形成零，隨著與絕對壓力之增加，輸出電壓呈直線地增 加之特性者。 但，可得知，現實的壓力感應器是當如前所述，氣體 溫度變化時，則不僅即使在相同氣體壓力下，感應器輸出 也會變化，且壓力-輸出特性無嚴密的直接關係。 (3) 1235825 具體而言，將施加於壓力感應器的壓力爲零時之感應 器輸出稱爲零點輸出，此零點受到溫度變化而變動之情事 稱爲零點輸出的溫度漂移。又，因加壓時的感應器輸出之 溫度所引起的變動稱爲跨距輸出的溫度漂移’爲了獲丫守正 確的感應器輸出，而必須進行零點輸出的溫度漂移與跨距 輸出的溫度漂移兩者的調整。 例如，假設爲無壓力感應器的零點輸出之溫度漂移’ 而該零點電壓爲〇 ( V )。又’當絕對壓力爲1 · 〇 ( X 102kPaA)也就是latm的壓力施加於此壓力感應器時之壓 力感應器的輸出電壓爲20mV。於在此狀態下使溫度改變 的情況時，當然該輸出電壓由20mV改變。此變動爲前述 跨距輸出的溫度漂移。實際上，由於會有零點輸出的溫度 漂移，故任意壓力之跨距輸出的溫度漂移爲加算零點電壓 的變動部分（零點輸出漂移）而出現。 如此，在一邊測定上游側壓力1^及/或下游側P2，一 邊控制漂移通過流量之壓力式流量控制裝置，由於在壓力 感應器的輸出電壓包含有零點輸出的溫度漂移與跨距輸出 的溫度漂移之溫度變動特性，故當將該輸出壓力直接變換 成壓力時，則會形成壓力P!、P2包含有誤差之情事。 因此’本發明者們是開發出：藉由控制電路或控制軟 體來自動修正因上述溫度變動所引起的壓力感應器之零點 輸出的溫度漂移及/或跨距輸出的溫度漂移，使得能夠更 正確地進行流體壓力或壓力控制、流量控制之系統技術， 此技術作爲日本特願200 1 -3999 1 0號而加以公開。 1235825 (4) 上述日本特願200 1 -3 999 1 0號之技術是能夠藉由較簡 單的結構之裝置大致完全地除去因這種壓力感應器的溫度 漂移所引起的壓力或流量等之控制誤差，而可達到優良的 實用效果。 但，最近可得知，在壓力感應器特別是使用了半導體 壓感元件的壓力感應器，不僅會有因上述流體溫度所引起 的輸出電壓之變動，也會有隨著時間變化之輸出電壓的變 動。 特別是上述壓力感應器的隨著時間變化之輸出電壓的 變動是在將孔口 F的二次側作成低壓（例如由1 (T4〜1 (T 6Torr的真空至ΙΟΟΤοηΟ之狀態提供使用之情況特別顯著 ，針對在將各種氣體供給至半導體製造裝置的處理室之裝 置所使用的壓力式流量控制裝置，變得無法忽視該影響。 一方面，考量：爲了除去上述壓力感應器的隨時間變 化之輸出變動的影響，使用另外設置壓力感應器的壓力-輸出特性之控制電路或控制軟體，人爲地使其滑動預定量 。但，另外設置用來修正這些隨時間變化的輸出變動（以 下稱爲壓力感應器的時間變化輸出漂移）之裝置是會造成 壓力控制裝置或流量控制裝置的製造成本上升，而形成一 大問題。 【發明內容】 [發明所欲解決之課題] 本發明是爲了解決以往之使用半導體感壓元件的壓力 -9- (5) 1235825 感應器或使用此感應器的流量•壓力控制裝置之上述問題 也就是 壓力感應器的壓力-輸出特性引起時間變化變動 ，使得流量·壓力等的控制精度惡化； 在另外設置修正 前述時間變化輸出漂移的手段之情況，導致流量·壓力控 制裝置的製造成本上升等之問題而開發完成的發明，其目 的在於提供一種，藉由有效地活用設在流量·壓力控制裝 置的壓力感應器的壓力-輸出特性的溫度漂移修正手段， 不會導致製造成本大幅提昇，並且能夠簡單且正確地修正 壓力感應器的時間變化零點漂移之壓力感應器及壓力控制 裝置以及壓力式流量控制裝置的自動零點修正裝置。 [用以解決課題之手段] 本發明者們是爲了分析因壓力感應器的隨時間變化所 引起的壓力-輸出變動，而不僅採用壓力感應器，並且採 用使用此感應器等的壓力控制裝置或壓力式流量控制裝置 ，反復進行以下所述的各種實驗。 由這些的實驗結果，可得知：在使用了半導體感應元 件的壓力感應器，①壓力感應器的零點會引起隨時間變化 ;②在真空封裝的條件下，零點的隨時間變化一定朝負側 變動（即，壓力-輸出特性的壓力〇之輸出値朝-（負）側 變動）；③當壓力感應器的零點朝-側變動時，則僅此變 動部分，壓力控制精度的誤差變動於+ (正）側（也就是 ，當壓力0之輸出値由零點朝-側例如僅相當於滿標輸出 電壓的0 · 2 %之電壓△ V朝-側變動時，則壓力控制精度的 -10- (6) 1235825 誤差僅上升相對於相當於滿標輸出電壓的0.2%之f )° 本發明是以上述所獲得的見解爲基礎而創作出 明，申請專利範圍第1項之發明，是以針對測定流 的壓力感應器，將來自於壓力感應器的感應器輸出 出至外部，並且將前述感應器輸出電壓輸入至壓力 的時間變化零點漂移修正手段，在該時間變化零點 正手段的感應器輸出判定手段，判定前述感應器輸 是否較設定値大，且在前述時間變化零點漂移修正 作動條件判定手段，判定壓力感應器的作動條件’ 壓力感應器輸出電壓較設定値大且壓力感應器的作 處於預先所設定的作動條件下時，除去壓力感應器 變化零點偏移的結構作爲發明的基本結構。 申請專利範圍第2項之發明是就申請專利範圍I 發明，其中以在壓力感應器使用半導體壓感元件， 過增幅器將感應器的輸出電壓輸出至外部’並且通 變換器輸出至壓力感應器的時間變化零點漂移修正 且當感應器輸出電壓較設定値大並且壓力感應器處 的作動條件時，由前述時間變化零點漂移修正手 D/A變換器，將與前述感應器輸出電壓相同電壓且 之零點修正用電壓輸出至前述增幅器之補償端子的 爲發明之基本結構。 申請專利範圍第3項之發明，是以針對具備壓 用控制閥與測定流體壓力的壓力感應器之壓力控制 S壓△ v 來的發 體壓力 電壓輸 感應器 漂移修 出電壓 手段的 當前述 用條件 的時間 I 1項之 又，通 過 A/D 手段， 於設定 段通過 逆極性 結構作 力控制 裝置， -11 - (7) 1235825 將來自於壓力感應器的感應器輸出電壓輸出至外部，並且 將前述感應器輸出電壓輸入至壓力感應器的時間變化零點 漂移修正手段，在該時間變化零點漂移修正手段的感應器 輸出判定手段，判定前述感應器輸出電壓是否較設定値大 ’且在前述時間變化零點漂移修正手段的作動條件判定手 段，判定壓力感應器的作動條件，當前述壓力感應器輸出 電壓較設定値大且壓力感應器的作用條件處於預先所設定 的作動條件下時，除去壓力感應器的時間變化零點偏移的 結構作爲發明之基本結構。 申請專利範圍第4項之發明是就申請專利範圍第3項之 發明，其中以在壓力感應器使用半導體壓感元件，又，通 過增幅器將感應器的輸出電壓輸出至外部，並且通過A/D 變換器輸出至壓力感應器的時間變化零點漂移修正手段， 且當感應器輸出電壓較設定値大並且壓力感應器處於設定 的作動條件時，由前述時間變化零點漂移修正手段通過 D/A變換器，將與前述感應器輸出電壓相同電壓且逆極性 之零點修正用電壓輸出至前述增幅器之補償端子的結構作 爲發明之基本結構。 申請專利範圍第5項之發明，是以針對由流量控制用 孔口、設在孔口的上游側配管之控制閥及設在孔口與控制 閥之間且用來檢測上游側壓力P!的上游側壓力感應器所構 成，藉由上游側壓力Pi來控制孔口通過流量之壓力式流量 控制裝置，將來自於壓力感應器的感應器輸出電壓輸出至 流量運算手段，並且將前述感應器輸出電壓輸入至壓力感 -12- 1235825 (8) 應器的時間變化零點漂移修正手段，在該時間變化零點漂 移修正手段的感應器輸出判定手段，判定前述感應器輸出 電壓是否較設定値大，且在前述時間變化零點漂移修正手 段的作動條件判定手段，判定壓力感應器的作動條件，當 前述壓力感應器輸出電壓較設定値大且壓力感應器的作用 條件處於預先所設定的作動條件下時，除去壓力感應器的 時間變化零點偏移的結構作爲發明之基本結構。 申請專利範圍第6項之發明是就申請專利範圍第5項之 發明，其中以在壓力感應器使用半導體壓感元件，又，通 過增幅器將感應器的輸出電壓輸出至外部，並且通過A/D 變換器輸出至壓力感應器的時間變化零點漂移修正手段， 且當感應器輸出電壓較設定値大並且壓力感應器處於設定 的作動條件時，由前述時間變化零點漂移修正手段通過 D/A變換器，將與前述感應器輸出電壓相同電壓且逆極性 之零點修正用電壓輸出至前述增幅器之補償端子的結構作 爲發明之基本結構。 申請專利範圍第7項之發明，是以針對由流量控制用 孔口、設在孔口的上游側配管之控制閥、設在孔口與控制 閥之間且用來檢測上游側壓力P!的上游側壓力感應器及設 在孔口的下游側配管且用來檢測下游側壓力P2所構成，藉 由上游側壓力與下游側壓力P2來控制孔口通過流量之 壓力式流量控制裝置，將來自於壓力感應器的感應器輸出 電壓輸出至流量運算手段，並且將前述感應器輸出電壓輸 入至壓力感應器的時間變化零點漂移修正手段，在該時間 -13- 1235825 (9) 變化零點漂移修正手段的感應器輸出判定手段，判定前述 感應器輸出電壓是否較設定値大，且在前述時間變化零點 漂移修正手段的作動條件判定手段，判定壓力感應器的作 動條件’當前述壓力感應器輸出電壓較設定値大且壓力感 應器的作用條件處於預先所設定的作動條件下時，除去壓 力感應器的時間變化零點偏移的結構作爲發明之基本結構 〇 申請專利範圍第8項之發明是就申請專利範圍第7項之 發明，其中以在壓力感應器使用半導體壓感元件，又，通 過增幅器將感應器的輸出電壓輸出至外部，並且通過A/D 變換器輸出至壓力感應器的時間變化零點漂移修正手段， 且當感應器輸出電壓較設定値大並且壓力感應器處於設定 的作動條件時，由前述時間變化零點漂移修正手段通過 D/A變換器，將與前述感應器輸出電壓相同電壓且逆極性 之零點修正用電壓輸出至前述增幅器之補償端子的結構作 爲發明之基本結構。 申請專利範圍第9項之發明是就申請專利範圍第3或4 項之發明，其中將在壓力感應器的時間變化零點漂移手段 的感應器輸出判定手段作爲基準的設定値，作爲相當於藉 由壓力感應器所檢測之滿標（full-scale )壓力的控制精度 以下之感應器輸出電壓。 申請專利範圍第1 0項之發明是就申請專利範圍第3或4 項之發明，其中將在壓力感應器的時間變化零點漂移手段 的作動條件判定手段作爲基準的設定作動條件，設成：有 -14- (10) 1235825 無對於控制閥的強制導通訊號、有無切斷訊號、及流量設 定訊號爲零之三個條件。 申請專利範圍第1 1項之發明是就申請專利範圍第5、6 、7或8項中任一項之發明，其中將在壓力感應器的時間變 化零點漂移手段的感應器輸出判定手段作爲基準的設定値 ，作爲相當於藉由壓力感應器所檢測之滿標壓力的控制精 度以下之感應器輸出電壓。 申請專利範圍第1 2項之發明是就申請專利範圍第5、6 、7或8項中任一項之發明，其中將在壓力感應器的時間變 化零點漂移手段的作動條件判定手段作爲基準的設定作動 條件，設成：有無對於控制閥的強制導通訊號、有無切斷 訊號、及流量設定訊號爲零之三個條件。 如申請專利範圍第丨3項之發明是就申請專利範圍第4 項之發明，其中由時間變化漂移修正手段將零點修正電壓 輸出至增幅器的補償端子之D/A變換器是與設在該壓力式 流量控制裝置的流量運算手段的壓力感應器的溫度漂移修 正手段共用。 如申請專利範圍第1 4項之發明是就申請專利範圍第6 或8項之發明，其中由時間變化漂移修正手段將零點修正 電壓輸出至增幅器的補償端子之D/A變換器是與設在該壓 力式流量控制裝置的流量運算手段的壓力感應器的溫度漂 移修正手段共用。 【實施方式】 -15- 1235825 (11) 首先，本發明者們是以如第2圖的形態將如第1圖所示 的構造之壓力感應器A安裝至管路B，藉由以真空泵浦將 管路B內保持於預定真空度的真空狀態，來調查測定感應 器A的壓力-輸出特性之隨時間變化。 在第1及第2圖，21爲感應器座、22爲感應器晶片（半 導體型壓感元件）、23爲隔膜、24爲隔膜座、25爲矽油、 26爲封裝體、27爲導銷、28爲安裝主體、29爲按壓螺帽、 3 0爲軸承、3 1爲密封環、P!爲氣體壓。 再者，在第2圖，使用按壓螺帽29將感應器A固定至 安裝主體2 8，但感應器A的安裝固定機構不論何種均可， 例如，亦可使用安裝固定用突緣（未圖示）將感應器A固 定至安裝主體28。 又，雖在第1及第2圖未圖示，但將所謂應變計固設於 隔膜2 3的內面側，不使用矽油2 5的構造之感應器A也替換 成第1圖構造的感應器A來使用。 藉由將配管路B內減壓，使得施加於隔膜2 3之氣體壓 P!改變，藉此，施加於感應器晶片2 2 (或應變計）的壓力 產生變動。其結果，來自於感應器晶片22的輸出電壓變化 ，檢測氣體壓P!的變動。 再者’由於感應益A其爲習知（日本特開平iq_82707 )者，故在此省略其說明。 第3圖是顯示：將感應器A安裝成如第2圖所示的狀態 ，在大氣壓下放置24小時後，保持成吸真空（真空度i〇-5 〜1(Γ6Τοη·)的狀態之情況時的感應器A之零點的變動狀 -16- 1235825 (12) 態的線圖。 由第3圖也可得知，在吸真空後大約1小時，零點是僅 朝負方向變動0.2〜0.3%FS (在將滿標FS作爲lOOTorr的 情況時，變動0.2〜0.3Torr )，然後在大約5小時左右後， 進一步朝負方向變動0.1 %FS後，並不穩定，變動量雖少 但朝負方向變動。 再者，第3圖的縱軸之壓力感應器（PT)的輸出是以 mV所顯示，2mV是相當於0.1%FS (即，0〜IOOToh相當 於輸出電壓0〜2V)。 第4圖是顯示在壓力感應器進行吸真空前對於所經歷 的壓力•時間的零點之穩定時間之影響者。即，使真空保 持試驗之程度零點爲穩定的狀態之試驗品經驗數種類的壓 力，然後，保持成真空而連續監視零點的穩定時間，調查 對於在吸真空前所經歷的壓力之零點穩定時間的影響。 由第4圖可得知，當經歷過的壓力高時則零點的初期 値高，對於吸真空後之朝負側的變動之比例逐漸變大。但 ，經過20〜30小時後，與事前所經歷過的壓力並無關係地 穩定於大致相同値，然後，與第3圖之根據真空放置之零 點穩定時間測定試驗的結果同樣地，以一定的比例持續減 少。再者，圖中之說明框所示的時間是由連續監視初期算 起的經過時間。 第5及第6圖是顯示：將壓力範圍以0 T 〇 r r (保持1 5秒 ，真空度大約爲10·6Τοη· ) -60Torr (保持30秒）規則且連 續地在每一天中5小時切換（第5圖）；及以OTorr (保持 -17- 1235825 (13) 15秒，真空度大約爲10_6T〇rr ) _01-iMPaG (保持3〇秒）規 則且連續地在每一天中5小時切換，分別經過5小時後測定 零點的變動之結果者，以大約1星期的間隔經過4周測定零 點的變動者。 由第5圖可得知，在1〜2周之間會有產生〇.2 %FS的零 點變動者。 又，由第6圖的試驗結果可得知，零點變動是朝負方 向穩定定於0.1%FS以下。 第7圖是顯示將感應器A連續保持於0.1MPG的加壓狀 態的情況時之零點輸出的隨時間變動者，可得知零點變動 是在正側以0.1 %FS以下的變動量產生。 由上述弟3至7圖所不的g式驗結果’可得知，在使用了 半導體反應元件（調變器）之感應器A，關於其零點輸出 的隨時間變化存在有下述之情事。 1 在真空保持、真空《60T〇rr的循環實驗，零點是 持續朝負方向變動。 在真空保持，初期的數時間變動特別大。 隨著時間經過，變動的情況減少，但當返回大氣壓或 置於0.1 MPaG的加壓狀態後進行吸真空時，則在初期會引 起較大的變動。 在真空〇60Torr的循環試驗，會有參差不齊，由真空 保持試驗也會產生變動量大者。在經過1週後，會有脫離 〇.2%FS 者。 根據0 · 1 Μ P a保持試驗的結果，在這種程度的加壓保 -18- 1235825 (14) 持，零點不會產生變動。又，在大氣壓下的保管狀態，也 不會有大的變動。 以如上述之感應器A的零點輸出之隨時間變化爲基礎 ，本發明者們是創造出自動修正不僅是感應器A，並且使 用感應器A之壓力控制裝置或壓力式流量控制裝置的零點 輸出之隨時間變化的方案。 以下，根據圖面說明關於本發明之修正壓力式流量控 制裝置的零點輸出之隨時間變化的自動零點調整裝置的實 施形態。 第8圖是本發明之利用了臨界條件的壓力式流量控制 裝置的構成圖。此壓力式流量控制裝置1是由於以所供給 的流體處於臨界條件的情況也就是由孔口 2所流出的流體 之流體流速呈音速的情況爲前提，故流量以Q = KPi表示， 壓力測定是僅以上游側壓力感應器3進行。 又，在壓力式流量控制裝置1，配置有：形成孔口 2a 之孔口 2、上游側配管4、下游側配管5、上游側壓力感應 器3、溫度感應器6、控制電路7、閥驅動部8以及控制閥9 〇 控制電路7是以電子電路、微電腦及內裝程式爲中心 所構成，由未圖示的增幅電路或A/D變換器等的電子電路 系統、運算根據試驗流量式之流量Qc的流量運算手段7 a 、指示欲流動的設定流量Qs之流量設定手段7b、以及計 算運算流量Qc與設定流量Qs之流量差△QCizQs-Qc或 Qc-Qs )之比較手段7c所組成。 -19- 1235825 (15) 再者，在第8圖，10爲氣體供給源、11爲壓力調整器 、12· 13爲閥、14爲處理室、15爲真空泵。 在根據真空泵15之排氣，孔口 2的下游側壓力P2是設 定成較上游側壓力h小很多，<大約0.5之臨界條件 是經常被自動地保持著。其結果，由孔口 2a所流出的氣 體速度形成音速，孔口 2的通過流量Q藉由Q = 來表示 〇 上游側壓力h是藉由壓力感應器3來測量。爲了進行 正確的壓力測定，壓力感應器3的感應器部分是接觸配置 於氣體流，並且不會攪亂氣體流地將該感應器部分設成極 小。因此，感應器部分相等於氣體溫度T。 又，氣體溫度T是藉由溫度感應器6所測量，溫度感 應器6是不會攪亂氣體流地測定孔口 2附近溫度，由於氣體 與孔口處於熱平衡的話則兩者的溫度相等，故將孔口溫度 作爲氣體溫度來測定。 上游側壓力P!與氣體溫度T是作爲電壓而獲得，藉 由未圖示的增幅電路或A/D變換器形成數位訊號。這些數 位訊號是輸入至流量運算手段7a，由氣體溫度T與氣體物 性算出比例係數K，又利用上游側壓力P!，運算流量QC 是根據（2〇 = &?1來算出。 由流量設定手段7 b輸入成爲目的之設定流量q s，藉 由比較手段7 C，將流量差△ Q作爲△ Q ：z Q s _ Q c來進行運算 〇 又，已被運算的流量差△ Q是輸出至閥驅動部8，在 -20· 1235825 (16) 將△ Q作成0之方向調整控制閥9之打開度。藉此進行此打 開度調整，可變調整氣體的孔口上游側壓力ρ 1 ’控制成根 據Qc = KPl所獲得的運算流量Qc相等於設定流量。 如前所述，壓力感應器3的感應器部分是相等於氣體 溫度T，當氣體溫度T變動時’則感應器部分的溫度也隨 其產生變化。又，壓力感應器3是具有溫度依存性’壓力 感應器3的輸出電壓隨著溫度變動而產生變動。因此，在 本發明之壓力式流量控制裝置，設有修正因如第9圖的壓 力感應器3之溫度所引起之輸出電壓的變動（漂移）之裝 置。 第9圖是在壓力式流量控制裝置，使用於修正因上述 溫度所引起的輸出電壓之變動（漂移）的手段中之零點輸 出（即，壓力爲零的狀態下之輸出電壓）的調整之零點輸 出的溫度漂移修正裝置之簡易方塊電路圖。 如第9圖所示，壓力感應器3的輸出電壓V是藉由固定 增幅電路16及可變增幅電路18增幅至壓力電壓V。壓力電 壓V是經由A/D變換器19輸入至CPU20。又，固定增幅電 路1 6的輸出是輸出至其他的可變增幅電路1 7，此可變增幅 電路17的輸出也賦予壓力電壓V，作爲上游側壓力？！顯示 於顯示板上。 前述壓力感應器3是假設當感受到例如絕對壓Pl = 7氣 壓（即，7 X 102kPaA )輸出lOOmV，藉由此壓力感應器3, 在P1=0〜3 ( X 102kPaA )的範圍控制上游側壓力Pd#，則 壓力感應器3的壓力電壓V是形成V = 0〜4 2.86mV範圍的 -21 - 1235825 (17) 輸出電壓。 又’右將此壓力電壓V的最大電壓42.86mV增幅至 滿標的5V，則增幅率形成117倍。在本實施形態，U7倍的 增幅率是錯由以則述固疋增幅電路1 6作成1 〇 〇倍、可_增· 幅電路1 7 · 1 8作成1 . 1 7倍可達到。 壓力感應器3的輸出電壓是受到溫度變動而漂移，現 在將壓力爲零時的輸出變動（漂移）稱爲零點溫度輸出、漂 移，而承受著任意壓力時的輸出變動（漂移）稱爲輸& @ 度漂移。 前述零點輸出溫度漂移是藉由調整固定增幅電路丨6的 補償端子1 6a來修正，具體而言，零點輸出漂移的修正是 藉由補償用D/A變換器40來達到。即，當壓力爲零時，顯 示壓力電壓V具有某値+v。，則將此零點輸出漂移電壓v。 作成零地將· v。出入至補償端子1 6 a。其結果，當壓力爲零 時，即使由壓力感應器3將輸出電壓V。出入至固定增幅電 路16，有效輸入電壓形成vd ( -V。）=〇，修正了零點輸出 的變動漂移。 前述補償用D/A變換器40是由粗調整用D/A變換器 40a與緩衝器40c、微調整用D/A變換器40b與緩衝器40d 及合成用緩衝器40e所構成。如此，藉由粗調整用電路與 微調整用電路，將反轉了零點輸出漂移電壓V。之零點修 正電壓-V。施加於補償端子1 6a，除去零點輸出漂移地加以 修正。1235825 (1) 发明 Description of the invention [Technical field to which the invention belongs] The present invention relates to a pressure sensor, a pressure control device, and a pressure type flow control device which are mainly used in semiconductor manufacturing equipment or chemical plants, and especially for measuring fluids. When the output of the pressure sensor changes with time, when the amount of change (drift) exceeds a predetermined setting, the zero point correction of the pressure sensor is automatically performed to prevent the following due to pressure detection. Pressure sensor or pressure control device and automatic zero point correction device of pressure type flow control device due to pressure or flow measurement error caused by time change. [Prior art] In semiconductor manufacturing equipment or chemical manufacturing equipment, it is required to control the supply flow rate or supply pressure of various raw materials with high accuracy. In response to these requirements, various types of pressure control devices or flow control devices have been developed. Pressure sensor used here. Figures 13 and 14 show an example of a conventional flow control device. In Figure 13 (US Patent No. 5 1 4694 1), the gas pressure P! On the upstream side of the orifice F and the orifice side are shown. The differential pressure Δ p between the inlet side of the F and the throat is input to the calculation means C, and based on the flow rate Wg and the set flow rate Wr calculated by the calculation means C, the control valve V is controlled via the valve controller VC to open the orifice. A so-called left-pressure type flow control device in which the gas flow rate on the downstream side is controlled to a set flow rate is known. Similarly, Fig. 14 (Japanese Unexamined Patent Publication No. 8-3 3 8 5 4 6) is an example of a pressure-type flow weight control device starting at (2) 1235825. The error is caused by a hole in a critical condition. The gas flow rate on the downstream side of the port is calculated as Qc = KPi (where P! Is the pressure upstream of the orifice), and the control valve v 'is opened and closed in a direction in which the difference between the set flow rate Qs and the calculated flow rate Qc becomes smaller. It is known to control the amount of gas flow 1 on the downstream side of the orifice F to the setting 値 'as a pressure-type flow control device used under the conditions of the first boundary (p2 / Pi ^ about 0.5). In addition, in the flow control device described above, it is necessary to detect the gas pressure p 1 and the like on the upstream side of the orifice F. In order to perform these pressure detections, a pressure sensor using a semiconductor pressure sensitive element such as a strain gauge is often used. [Patent Document 1] US Patent No. 5 1 4694 1 [Patent Document 2] Japanese Patent Application Laid-Open No. 8-33 8546 The pressure sensor that detects the aforementioned fluid pressure P 1 is based on the environmental conditions around the sensor, such as gas temperature, etc. , We can know that its output 値 changes. That is, even if a pressure sensor arranged in the same fluid pressure is subjected to a fluid temperature change, the output of the pressure sensor 値 also varies. For example, in the aforementioned strain gage type pressure sensor, the pressure changes into a voltage, forming the relationship between the vertical axis corresponding to the output voltage when the horizontal axis is taken as the pressure. As the output characteristic, it is desirable that the output voltage becomes zero when the absolute pressure is zero, and the output voltage increases linearly as the absolute pressure increases. However, it can be known that, as described above, when the gas temperature changes, not only the sensor output changes even under the same gas pressure, but the pressure-output characteristics have no direct direct relationship. (3) 1235825 Specifically, the sensor output when the pressure applied to the pressure sensor is zero is referred to as the zero point output, and the change of the zero point due to temperature changes is referred to as the temperature drift of the zero point output. In addition, the change caused by the temperature of the sensor output during pressurization is called the temperature drift of the span output. In order to obtain the correct sensor output, the temperature drift of the zero output and the temperature drift of the span output must be performed. Adjustment of both. For example, suppose the temperature drift of the zero output of a pressureless sensor 'and the zero voltage is 0 (V). Also, when the absolute pressure is 1 · 〇 (X 102kPaA), that is, the pressure of laTM is applied to the pressure sensor, the output voltage of the pressure sensor is 20mV. When the temperature is changed in this state, of course, the output voltage is changed by 20mV. This change is the temperature drift of the aforementioned span output. Actually, there will be a temperature drift of the zero output, so the temperature drift of the span output at any pressure appears as the fluctuation part of the zero voltage (zero output drift) is added. In this way, while measuring the upstream pressure 1 ^ and / or the downstream side P2, the pressure-type flow control device that controls the drift through flow rate, because the output voltage of the pressure sensor includes the temperature drift of the zero output and the temperature of the span output Due to the temperature fluctuation characteristics of the drift, when the output pressure is directly converted into the pressure, the pressures P! And P2 will be included. Therefore, the present inventors have developed: by the control circuit or control software to automatically correct the temperature drift of the zero point output of the pressure sensor and / or the temperature drift of the span output caused by the above temperature fluctuation, so that it can be more accurate System technology for fluid pressure, pressure control, and flow control in the field is disclosed as Japanese Patent Application No. 200 1 -3999 10. 1235825 (4) The above-mentioned Japanese Patent Application No. 200 1 -3 999 1 0 technology can completely remove the control of pressure or flow caused by the temperature drift of such a pressure sensor by a relatively simple device. Error, and can achieve excellent practical results. However, it has recently been learned that in pressure sensors, especially pressure sensors using semiconductor pressure sensing elements, not only the output voltage changes due to the above-mentioned fluid temperature, but also the output voltage changes over time. change. In particular, the change in the output voltage of the pressure sensor over time is that the secondary side of the orifice F is made to a low voltage (for example, it is provided for use from a vacuum of 1 (T4 ~ 1 (T 6Torr to ΙΟΟΤοηΟ). Significantly, this effect cannot be ignored for a pressure-type flow control device used in a device that supplies various gases to a processing chamber of a semiconductor manufacturing device. On the one hand, consider: in order to remove the time-varying output of the pressure sensor described above The effect of the fluctuation is controlled by using a control circuit or control software that separately sets the pressure-output characteristics of the pressure sensor to artificially slide it by a predetermined amount. However, another setting is used to correct these time-varying output fluctuations (hereinafter referred to as pressure). The time-varying output drift of an inductor) device causes a rise in the manufacturing cost of a pressure control device or a flow control device, which poses a major problem. [Summary of the Invention] [Questions to be Solved by the Invention] The present invention is intended to solve the conventional problems Pressure using a semiconductor pressure sensing element -9- (5) 1235825 sensor or flow using this sensor • The above problem of the pressure control device is that the pressure-output characteristics of the pressure sensor cause changes in time, which deteriorates the control accuracy of the flow rate and pressure. In the case where a means for correcting the aforementioned time-varying output drift is additionally set, the flow rate and pressure are caused. An object of the invention, which is developed based on problems such as increase in manufacturing cost of a control device, is to provide a temperature drift correction method that effectively utilizes the pressure-output characteristics of a pressure sensor provided in a flow rate and pressure control device. A pressure sensor and a pressure control device capable of easily and accurately correcting a time change and a zero drift of a pressure sensor, and an automatic zero correction device of a pressure type flow control device, which lead to a significant increase in manufacturing cost. [Methods for solving problems] This In order to analyze the pressure-output variation caused by the pressure sensor's change over time, the inventors used not only the pressure sensor, but also a pressure control device or pressure-type flow control device using this sensor, etc., and iteratively performed the following Various experiments described From these experimental results, it can be known that: in a pressure sensor using a semiconductor sensing element, ① the zero point of the pressure sensor will cause changes with time; ② under vacuum packaging conditions, the zero point must change to the negative side with time. Variation (that is, the output of pressure 0 of the pressure-output characteristic fluctuates toward the-(negative) side); ③ When the zero point of the pressure sensor fluctuates toward the-side, only this variation part, the error of the pressure control accuracy varies by + (Positive) side (that is, when the output of pressure 0 changes from zero to the-side, for example, the voltage △ V corresponding to only 0. 2% of the full-scale output voltage changes toward the-side, the pressure control accuracy is -10- (6) 1235825 The error only increases relative to 0.2% of the full-scale output voltage. F) The invention is based on the insights obtained above. The invention in the first scope of the patent application is aimed at A pressure sensor for measuring the flow, which outputs the sensor output from the pressure sensor to the outside, and inputs the aforementioned sensor output voltage to the time change zero drift correction means of the pressure. The sensor output determination means of the positive means determines whether the above-mentioned sensor output is larger than the setting, and determines the operating condition of the pressure sensor during the aforementioned time-varying zero drift correction operation condition determination means. The pressure sensor output voltage is larger than the setting. In addition, when the operation of the pressure sensor is under a preset operating condition, a structure in which the pressure sensor changes the zero offset is removed as the basic structure of the invention. The invention in the second scope of the patent application is the invention in the scope of patent application I, in which a semiconductor pressure-sensing element is used in the pressure sensor, and the output voltage of the sensor is output to the outside through the amplifier, and is output to the pressure sensor through a converter. When the output voltage of the sensor is larger than the set value and the operating condition at the pressure sensor, the manual D / A converter will be the same voltage as the output voltage of the sensor. The output of the zero-point correction voltage to the compensation terminal of the aforementioned amplifier is the basic structure of the invention. The invention of item 3 in the scope of the patent application is based on the above-mentioned means for repairing the voltage of the transducer pressure and pressure sensor drift from the pressure control S pressure △ v provided with the pressure control valve and the pressure sensor for measuring the pressure of the fluid. The conditional time I is one of the other terms. Through the A / D method, a reverse polarity structure is used to set the force control device at the set stage. -11-(7) 1235825 outputs the sensor output voltage from the pressure sensor to the outside, and The time-varying zero-point drift correction means for inputting the aforementioned sensor output voltage to the pressure sensor, and the sensor output determination means of the time-varying zero-point drift correction means determine whether the output voltage of the sensor is larger than the set value and within the aforementioned time The operating condition determining means for changing the zero drift correction means determines the operating condition of the pressure sensor. When the output voltage of the pressure sensor is larger than the set value and the operating condition of the pressure sensor is under the preset operating condition, the pressure sensor is removed. The time-varying zero-shift structure of the device is used as the basic structure of the invention. The invention in item 4 of the scope of patent application is the invention in item 3 of the scope of patent application, in which a semiconductor pressure-sensing element is used in a pressure sensor, and an output voltage of the sensor is output to the outside through an amplifier, and the A / The time-varying zero-drift correction method for the D converter output to the pressure sensor, and when the sensor output voltage is larger than the set and the pressure sensor is in the set operating condition, the aforementioned time-varying zero-drift correction method passes the D / A conversion. The structure in which the zero-point correction voltage with the same polarity as the output voltage of the inductor and the reverse polarity is output to the compensation terminal of the amplifier as the basic structure of the invention. The invention in the scope of patent application No. 5 is aimed at detecting the upstream pressure P! From a flow control orifice, a control valve provided on the upstream side of the orifice, and a control valve provided between the orifice and the control valve. A pressure-type flow control device composed of an upstream pressure sensor that controls the flow rate of the orifice by the upstream pressure Pi, outputs the output voltage of the sensor from the pressure sensor to a flow calculation means, and outputs the aforementioned sensor. Voltage input to the pressure sensor-12-1235825 (8) The time change zero shift correction method of the responder, and the sensor output determination means of the time change zero shift correction method determines whether the aforementioned output voltage of the inductor is larger than the set value, and The operating condition determining means of the aforementioned time-varying zero-drift correction means determines an operating condition of the pressure sensor. When the output voltage of the pressure sensor is larger than a set value and the operating condition of the pressure sensor is under a preset operating condition, The structure that removes the time-varying zero point of the pressure sensor is the basic structure of the invention. The invention in the 6th scope of the patent application is the invention in the 5th scope of the patent application, in which a semiconductor pressure-sensing element is used in a pressure sensor, and the output voltage of the sensor is output to the outside through an amplifier, and through A / The time-varying zero-drift correction method for the D converter output to the pressure sensor, and when the sensor output voltage is larger than the set and the pressure sensor is in the set operating condition, the aforementioned time-varying zero-drift correction method passes the D / A conversion. The structure in which the zero-point correction voltage with the same polarity as the output voltage of the inductor and the reverse polarity is output to the compensation terminal of the amplifier as the basic structure of the invention. The seventh invention in the scope of patent application is for detecting the upstream pressure P! From the orifice for flow control, the control valve provided on the upstream piping of the orifice, and between the orifice and the control valve. The upstream pressure sensor and the downstream piping provided at the orifice are used to detect the downstream pressure P2. The pressure-type flow control device that controls the flow rate of the orifice through the upstream pressure and the downstream pressure P2. Time change zero drift correction means for outputting the sensor output voltage of the pressure sensor to the flow rate calculation means, and inputting the aforementioned sensor output voltage to the pressure sensor, at this time -13-1235825 (9) change zero point drift correction means The sensor output determination means determines whether the output voltage of the aforementioned sensor is larger than the set value, and determines the operating condition of the pressure sensor during the aforementioned time-varying zero-point drift correction means to determine the operating condition of the pressure sensor. Remove the pressure sensor when the setting is large and the operating conditions of the pressure sensor are under the preset operating conditions. The time-shifted zero-point shift structure is the basic structure of the invention. The invention in the eighth patent application is the invention in the seventh patent application, in which a semiconductor pressure sensitive element is used in a pressure sensor, and an amplifier is used. The sensor output voltage is output to the outside, and the time-varying zero-drift correction means is output to the pressure sensor through the A / D converter, and when the sensor output voltage is larger than the setting and the pressure sensor is in the set operating condition By means of the aforementioned time-varying zero-point drift correction means, the structure of outputting the zero-point correction voltage of the same voltage as the output voltage of the inductor to the compensation terminal of the aforementioned amplifier through the D / A converter as the basic structure of the invention. The invention of the 9th scope of the patent application is the invention of the 3rd or 4th scope of the patent application, in which the sensor output determination means of the time change zero shift means of the pressure sensor is used as a reference setting. The output voltage of the sensor below the control accuracy of the full-scale pressure detected by the pressure sensor. The invention of item 10 in the scope of patent application is the invention in item 3 or 4 of the scope of patent application, in which the operating condition determination means of the time change zero drift means of the pressure sensor as a reference is used to set the operating conditions as follows: -14- (10) 1235825 There are no three conditions for the forced pilot signal for the control valve, the presence or absence of the cut-off signal, and the flow setting signal being zero. The invention of claim 11 is the invention of any one of claims 5, 6, 7, or 8, in which the sensor output determination means of the time change zero drift of the pressure sensor is used as a reference The setting of 値 is the output voltage of the sensor equivalent to the control accuracy of the full-scale pressure detected by the pressure sensor. The invention in item 12 of the scope of patent application is an invention in any one of the scope of patent application 5, 6, 7, or 8 in which the operating condition determination method of the time change zero shift means of the pressure sensor is used as a reference The operating conditions are set to three conditions: the presence or absence of a forced pilot signal for the control valve, the presence or absence of a cutoff signal, and the flow setting signal of zero. For example, the invention in the third scope of the patent application is the invention in the fourth scope of the patent application, in which the time-varying drift correction means outputs the zero-point correction voltage to the compensation terminal of the amplifier. The temperature drift correction means of the pressure sensor of the flow rate calculation means of the pressure type flow control device is used in common. For example, the invention in the 14th scope of the patent application is the invention in the 6th or 8th scope of the patent application, in which the D / A converter that outputs the zero correction voltage to the compensation terminal of the amplifier by the time-varying drift correction means is designed with The temperature drift correction means of the pressure sensor is used in the flow rate calculation means of the pressure type flow control device. [Embodiment] -15-1235825 (11) First, the present inventors installed a pressure sensor A having a structure shown in FIG. 1 to a pipeline B in a form as shown in FIG. 2 and vacuum-pumped it. The vacuum state of the pipe B was maintained at a predetermined vacuum degree, and the pressure-output characteristics of the sensor A were measured and measured over time. In the first and second figures, 21 is an inductor holder, 22 is an inductor chip (semiconductor pressure sensor), 23 is a diaphragm, 24 is a diaphragm holder, 25 is silicone oil, 26 is a package body, 27 is a guide pin, 28 is a mounting body, 29 is a pressing nut, 30 is a bearing, 31 is a seal ring, and P! Is a gas pressure. In addition, in FIG. 2, the sensor A is fixed to the mounting body 28 using the pressing nut 29, but the mounting mechanism of the sensor A may be any type. For example, a flange (not shown) for mounting and fixing may be used. (Illustrated) Fix the sensor A to the mounting body 28. In addition, although not shown in Figs. 1 and 2, the so-called strain gauge is fixed on the inner surface side of the diaphragm 23, and the sensor A having a structure without using silicone oil 25 is also replaced with a sensor having a structure shown in Fig. 1. Device A to use. By reducing the pressure in the piping line B, the gas pressure P! Applied to the diaphragm 23 is changed, thereby changing the pressure applied to the sensor chip 2 2 (or the strain gauge). As a result, the output voltage from the sensor chip 22 changes, and a change in the gas pressure P! Is detected. Furthermore, since the induction benefit A is a conventional one (Japanese Patent Application Laid-Open No. iq_82707), its explanation is omitted here. Fig. 3 shows the state where the sensor A is installed as shown in Fig. 2 and left for 24 hours under atmospheric pressure, and then maintained in a state of vacuum suction (vacuity i0-5 to 1 (Γ6Τοη ·). The state of the zero point of the sensor A at the time -16-1235825 (12) state diagram. It can also be seen from Figure 3 that after about 1 hour after vacuuming, the zero point is only 0.2 ~ 0.3% in the negative direction. FS (When the full-scale FS is taken as 100 Torr, the variation is 0.2 to 0.3 Torr), and then after about 5 hours, it is further changed by 0.1% in the negative direction. After FS, it is unstable, and the amount of variation is small but negative. In addition, the output of the pressure sensor (PT) on the vertical axis of FIG. 3 is shown in mV, and 2 mV is equivalent to 0.1% FS (that is, 0 to 100 oh is equivalent to the output voltage 0 to 2 V). Section 4 The figure shows the influence of the settling time on the zero point of the pressure / time experienced before the pressure sensor performs the vacuum. That is, the number of types of pressure experienced by the test article that stabilized the zero point of the vacuum holding test. , Keep in vacuum and continuously monitor the stabilization time of zero point, investigate the The effect of the settling time of the zero point of the pressure before the vacuum is drawn. From Figure 4, it can be seen that when the pressure experienced is high, the initial value of the zero is high, and the proportion of the change to the negative side after vacuum is gradually increased. However, after 20 to 30 hours, the pressure has stabilized at approximately the same level regardless of the pressure experienced in advance. Then, the result is the same as the result of the zero-point stabilization time measurement test in vacuum placed in Figure 3, It continues to decrease at a certain ratio. In addition, the time indicated by the description box in the figure is the elapsed time from the initial stage of continuous monitoring. Figures 5 and 6 show that the pressure range is set to 0 T 〇rr (hold 1 5 seconds, the vacuum degree is about 10 · 6Τοη ·) -60Torr (30 seconds hold) Regular and continuous switching for 5 hours in each day (Figure 5); and OTorr (hold -17-1235825 (13) 15 seconds) , Vacuum degree is about 10_6T〇rr) _01-iMPaG (maintained for 30 seconds) regular and continuous switching for 5 hours in each day, and the results of measuring the change of zero point after 5 hours, respectively, pass at about one week intervals Measurement of zero point change in 4 weeks It can be seen from Fig. 5 that there will be a zero change of 0.2% FS between 1 and 2 weeks. From the test results of Fig. 6, it can be seen that the zero change is stable in the negative direction. Below 0.1% FS. Figure 7 shows the time-dependent change of the zero output when the sensor A is continuously maintained at a pressure of 0.1MPG. It can be seen that the zero change is 0.1% FS or less on the positive side. It can be seen from the g-type test results not shown in Figures 3 to 7 above that the sensor A using a semiconductor response element (modulator) has a time-dependent change in its zero output. The following matters. 1 In a vacuum experiment with a vacuum of 60 Torr, the zero point is continuously changing in the negative direction. During vacuum holding, the initial time and time fluctuations are particularly large. As time passes, the number of fluctuations decreases, but when the vacuum is returned after returning to atmospheric pressure or a pressurized state of 0.1 MPaG, large fluctuations may be caused in the initial stage. In the vacuum cycle test of 60 Torr, there will be unevenness, and a large amount of fluctuation will also occur in the vacuum holding test. After 1 week, there will be 0.2% FS. According to the results of the holding test of 0.1 MPa, at this level of pressure, the zero point will not change. In addition, the storage state under atmospheric pressure does not change greatly. Based on the time-dependent change of the zero output of the sensor A as described above, the inventors have created an automatic correction that uses not only the sensor A but also the zero output of the pressure control device or pressure type flow control device of the sensor A A program that changes over time. Hereinafter, an embodiment of an automatic zero adjustment device that changes with time of the zero output of the corrected pressure type flow control device of the present invention will be described with reference to the drawings. Fig. 8 is a block diagram of a pressure type flow control device using a critical condition of the present invention. This pressure type flow control device 1 is based on the premise that the supplied fluid is in a critical condition, that is, the flow velocity of the fluid flowing out of the orifice 2 is at the speed of sound. Therefore, the flow rate is expressed by Q = KPi, and the pressure measurement is Only with the upstream pressure sensor 3. The pressure-type flow control device 1 is provided with an orifice 2 forming an orifice 2a, an upstream pipe 4, a downstream pipe 5, an upstream pressure sensor 3, a temperature sensor 6, a control circuit 7, and a valve drive. The part 8 and the control valve 9 The control circuit 7 is mainly composed of an electronic circuit, a microcomputer, and a built-in program, and includes an electronic circuit system such as an amplifier circuit or an A / D converter (not shown), and calculations based on the test flow rate formula. The flow rate calculation means 7a of the flow rate Qc, the flow rate setting means 7b indicating the set flow rate Qs to flow, and the comparison means 7c that calculates the flow rate difference (QCizQs-Qc or Qc-Qs) between the calculated flow rate Qc and the set flow rate Qs. -19- 1235825 (15) Furthermore, in Fig. 8, 10 is a gas supply source, 11 is a pressure regulator, 12 · 13 is a valve, 14 is a processing chamber, and 15 is a vacuum pump. In the exhaust by the vacuum pump 15, the pressure P2 on the downstream side of the orifice 2 is set to be much smaller than the pressure h on the upstream side, and the critical condition of < 0.5 is always automatically maintained. As a result, the speed of sound is formed by the velocity of the gas flowing out of the orifice 2a, and the passing flow rate Q of the orifice 2 is represented by Q =. The upstream pressure h is measured by the pressure sensor 3. In order to perform accurate pressure measurement, the sensor portion of the pressure sensor 3 is disposed in contact with the gas flow, and the sensor portion is made extremely small without disturbing the gas flow. Therefore, the inductor portion is equal to the gas temperature T. In addition, the gas temperature T is measured by the temperature sensor 6, which measures the temperature near the orifice 2 without disturbing the gas flow. Because the gas and the orifice are in thermal equilibrium, the temperature of the two is equal, so The orifice temperature was measured as the gas temperature. The upstream pressure P! And the gas temperature T are obtained as voltages, and a digital signal is formed by an amplifier circuit (not shown) or an A / D converter. These digital signals are input to the flow rate calculation means 7a, and the proportionality coefficient K is calculated from the gas temperature T and the physical properties of the gas, and the upstream pressure P! Is used to calculate the flow rate QC based on (2〇 = &? 1. Set by the flow rate Means 7 b inputs the set flow rate qs for the purpose, and compares the means 7 C to calculate the flow rate difference Δ Q as Δ Q: z Q s _ Q c. Furthermore, the calculated flow rate difference Δ Q is output to The valve driving unit 8 adjusts the opening degree of the control valve 9 in the direction of -20 · 1235825 (16) by setting △ Q to 0. With this opening degree adjustment, the upstream pressure ρ 1 ′ of the orifice of the gas can be variably adjusted. The calculated flow rate Qc obtained according to Qc = KPl is equal to the set flow rate. As mentioned earlier, the sensor part of the pressure sensor 3 is equal to the gas temperature T. When the gas temperature T changes, the temperature of the sensor part is also It changes with it. In addition, the pressure sensor 3 is temperature-dependent. The output voltage of the pressure sensor 3 varies with temperature. Therefore, the pressure type flow control device of the present invention is provided with a correction factor such as 9 of Device for fluctuation (drift) of output voltage caused by temperature of pressure sensor 3. Figure 9 shows a pressure-type flow control device used to correct the fluctuation (drift) of output voltage caused by the temperature. Simple block circuit diagram of the zero-point temperature drift correction device for adjusting the zero-point output (that is, the output voltage in a state where the pressure is zero). As shown in FIG. 9, the output voltage V of the pressure sensor 3 is increased by a fixed amount. The circuit 16 and the variable amplifier circuit 18 are amplified to a pressure voltage V. The pressure voltage V is input to the CPU 20 via the A / D converter 19. The output of the fixed amplifier circuit 16 is output to other variable amplifier circuits 17, The output of this variable amplifier circuit 17 is also given a pressure voltage V as an upstream pressure? Displayed on the display panel. The aforementioned pressure sensor 3 is assumed to be felt when, for example, the absolute pressure Pl = 7 atmospheres (ie, 7 X 102kPaA) Output 100mV. By this pressure sensor 3, control the upstream pressure Pd # in the range of P1 = 0 ~ 3 (X 102kPaA), then the pressure voltage V of the pressure sensor 3 is formed V = 0 ~ 4 2.86mV range -21-1235825 (17) output voltage. When the maximum voltage of this pressure voltage V is increased from 42.86mV to 5V, the increase rate is 117 times. In this embodiment, the U7 increase rate is wrong. In the following description, the solid-state amplifier circuit 16 can be made by a factor of 1000, and the amp-amp circuit can be made by 17 · 18, which can be achieved by 1. 17 times. The output voltage of the pressure sensor 3 is subject to temperature fluctuations. The output variation (drift) when the pressure is zero is referred to as zero temperature output and drift, and the output variation (drift) when subjected to any pressure is referred to as & @degree drift. The aforementioned zero output temperature drift is corrected by adjusting the compensation terminal 16a of the fixed amplifier circuit 6; specifically, the correction of the zero output drift is achieved by the compensation D / A converter 40. That is, when the pressure is zero, the display pressure voltage V has a certain 値 + v. , Then this zero point outputs a drift voltage v. Create zero ground will v. Access to the compensation terminal 1 6 a. As a result, when the pressure is zero, the voltage V is outputted by the pressure sensor 3 even. When entering or leaving the fixed-amplifier circuit 16, the effective input voltage forms vd (-V.) = 0, which corrects the drift of the zero output. The compensation D / A converter 40 is composed of a coarse adjustment D / A converter 40a and a buffer 40c, a fine adjustment D / A converter 40b and a buffer 40d, and a synthesis buffer 40e. In this way, the coarse adjustment circuit and the fine adjustment circuit invert the zero-point output drift voltage V. Zero-point correction voltage -V. It is applied to the compensation terminal 16a to correct the zero output drift.
第1 0圖是零點輸出電壓的變動漂移之修正與滿標F S -22- (18) 1235825 的設定之關係的說明圖，橫軸顯示上游側壓力p]，縱軸顯 示壓力感應器3的輸出電壓v與可變增幅電路18之壓力電 壓V。壓力範圍是p】 = 〇〜Pim，最大壓力Plm爲3·〇(χ l(TkPaA )。又，當氣體溫度τ爲τ〇時，零點輸出漂移作 爲爲v^UmV，最大壓力P]m之感應器的最大輸出電壓 作爲 v1：=40.8mV。 如此’第1 0圖之連結v。與v }之點線a，顯示壓力感應 器3之溫度特性，在此，當將4。施加於補償端子1 6a時， 則根據ve ( - v。）二0，v。是形成〇mv，由v。修正成零（箭 號a)。其結果，最大壓力Plm之感應器輸出電壓也形成 Vc+ ( -V。）=40.8 + 2.0 = 42.8mV。因此，壓力感應器3的輸出 是藉由零點漂移修正，修正至0〜42.8mV。此修正後的溫 度特性由虛線a”所顯示。 其次，進行此壓力感應器3的滿標設定。當零點調整 後的壓力感應器之輸出爲〇〜ι+(-ν。）也就是〇〜42.8mV 時，將此設定成滿標5V。即，將42.8Mv增幅至5V，故將 可變增幅器44、46的增幅率作爲1.17，其結果’ 2段增幅 率是設定成Μ = 1 0 〇 X 1.1 7 = 1 1 7。此修正是以箭號6所顯示。 因此，最大電壓 ν m是以 V = ( ν 1 -ν。）所賦予’在任 意壓力Ρ!的壓力感應器3之輸出電壓ν是增幅至V = M(v_ v。）。此增幅輸出V是以實線C所顯示’在臨界條件下’ 此實線C顯示V = a ( T 〇 ) P1 °比例定數a ( T ◦)是賦予氣 體溫度T爲T◦之比例定數。Fig. 10 is an explanatory diagram of the relationship between the correction of the fluctuation of the zero-point output voltage and the setting of the full-scale FS -22- (18) 1235825. The horizontal axis shows the upstream pressure p], and the vertical axis shows the output of the pressure sensor 3. The voltage v and the pressure voltage V of the variable amplifier circuit 18. The pressure range is p] = 〇 ~ Pim, the maximum pressure Plm is 3 · 〇 (χ l (TkPaA). Also, when the gas temperature τ is τ〇, the zero output drift is v ^ UmV, the maximum pressure P] m The maximum output voltage of the sensor is v1: = 40.8mV. In this way, the dotted line “a” of FIG. 10 and the point line a of v} show the temperature characteristics of the pressure sensor 3. Here, when 4. is applied to the compensation For terminal 16a, 0mv is formed according to ve (-v.), And 0, v. Is modified from v. To zero (arrow a). As a result, the output voltage of the inductor with the maximum pressure Plm also forms Vc + ( -V.) = 40.8 + 2.0 = 42.8mV. Therefore, the output of the pressure sensor 3 is corrected to 0 ~ 42.8mV by zero drift correction. The temperature characteristics after this correction are shown by the dotted line a ". Next, proceed The full scale setting of this pressure sensor 3. When the output of the zero pressure adjusted pressure sensor is 0 ~ ι + (-ν.) Which is 0 ~ 42.8mV, set this to full scale 5V. That is, set 42.8 The Mv increases to 5V, so the increase rate of the variable amplifiers 44 and 46 is 1.17. As a result, the two-stage increase rate is set to M = 1 0 0X 1.1 7 = 1 1 7. This correction is shown by arrow 6. Therefore, the maximum voltage ν m is given by V = (ν 1-ν.) Given by the output voltage ν of the pressure sensor 3 at an arbitrary pressure P! Is the increase to V = M (v_ v.). This increase output V is shown in the solid line C 'under critical conditions'. This solid line C shows V = a (T 〇) P1 ° proportional constant a (T ◦ ) Is a proportional constant that gives the gas temperature T to T◦.
在上述第9及1 〇圖的說明’零點輸出漂移v。- 2 · 0 m V -23- 1235825 (19) 爲受到流體（氣體）的溫度變化所產生者。因此’將 a，作爲壓力感應器輸出v的溫度特性，而直線C作爲 器輸出V之溫度特性。 一方面，在本發明，由於是以壓力感應器輸出v 時間變化的零點修正作爲問題，故若將前述第9及第 的零點輸出漂移V。（即，壓力零之壓力感應器輸出v。 定爲因隨時間變化所產生的零點輸出漂移的話’則在 於第9及第10圖所說明過之修正手段或其與滿標（FS 設定之關係直接能以因隨時間變化所產生的零點輸出 之修正加以適用。 即，將前述第1 0圖之直線a，作爲壓力感應器輸出 隨時間變化特性，而直線C作爲增幅器輸出V的隨 變化特性加以掌握即可。 再者，關於前述第3至6圖所示的壓力感應器3之 v的隨時間變化特性之測定方法，在此省略其詳細說 使將壓力感應器3組裝成如第2圖所示的形態之管路B 壓力以真空泵（未圖示）作成零壓力（真空i〇_5〜10“ )也就是Pi与〇 ( X 1 0」kPaA )，測定時間經過與壓力 器3的零點輸出之變動量V。（漂移電壓v。） ’或在將 B內的壓力保持於任意的設定値之狀態下測定時間經 壓力感應器3的零點輸出之變動量V。者° 前述第3圖是顯示保持於真空下的情況時之壓力 器3的因時間變化所引起的零點輸出漂移之一例’爲 變化輸出特性圖，橫軸爲時間（H r )、縱軸爲零點輸 直線 增幅 的隨 10圖 )規 先則 )的 漂移 V的 時間 輸出 明， 內的 5Torr 感應 管路 過與 感應 時間 出漂 -24 - 1235825 (20) 移電壓v。，感應器輸出電壓2mV爲相當於將滿標作爲 lOOTorr時的滿標FS之0.1%者。PT輸出OmV的線是顯示 無漂移的理想情況，曲線是實際測定到的零點輸出漂移。 此漂移是因壓力感應器的樣品不同而不同，但如前所述， 在大約1小時後，形成0.2〜0.3 % F S ( v。= 4〜6 m V )，在大 約6小時後形成0.4%FS ( v^8mV )程度。此零點輸出漂移 電壓v。是施加於前述第9圖的固定增幅電路1 6之補償端子 1 6 a 〇 在本發明，當壓力感應器3之因時間變化所引起的零 點輸出漂移v。變得較-0.13 %FS (即，零點輸出漂移v。爲-2.6 m V )大時，則將零點輸出漂移v。施加至如第9圖的固 定增幅電路16之補償端子16a，自動地進行壓力感應器3的 零點調整。 再者，將前述- 0.13 %FS作爲隨時間變化的零點漂移之 調整基準點是由於由如第3至6圖所示的基礎試驗的結果， 可得知在真空保持下，零點輸出漂移v。僅發生於負方向 ;及若爲-0.3%FS ( Vf2.6mV )程度的零點漂移的話，可 處於壓力感應器3之實用上的容許誤差之範圍內等之故。 具體而言，首先判斷壓力感應器3的輸出電壓v是否 形成於負側。 再者，於壓力控制裝置使用中，一定有氣體壓施壓在 壓力感應器3，壓力感應器3的輸出電壓v不會形成於負側 。因此，若判定爲壓力感應器3的輸出電壓v位於負側的 話，則可得知，壓力控制裝置處於停止使用中，無氣體流 -25- 1235825 (21) 通。 又，因在真空保持下，壓力感應器3的 所引起之零點輸出電壓漂移v。一定出現於-以，若壓力感應器3的輸出漂移位於-側的話 器3是保持於真空或接近真空之真空度（1〇\ 右）。 因此，由於若辨識壓力感應器3的輸出賓 於-側的話則壓力式流量控制裝置是處於不 且管路內壓力保持於接近真空的狀態，故不 行因隨時間變化所引起之零點漂移的調整。 其次，判定壓力感應器3的輸出電壓漂卷 前述設定値（v = -0.13%FS )。然後，若在壓 出漂移v超過設定値的情況時，自己診斷須 應器3之隨時間變化所引起的零點漂移之調 進行零點漂移V。的調整。 第1 1圖是壓力控制裝置的控制電路之詳 。壓力感應器3、固定增幅電路16、可變增 、A/D變換器19、補償用D/A變換器40等I 的情況相同，故省略其說明。 再者，壓力式流量控制裝置的控制電路 情況大致相同，僅在流量運算手段中的流量 7 a ’的輸出側設有氣體溫度修正部（未圖示 於溫度感應器6的溫度檢測訊號輸入至此氣 的這一點與第1 1圖不同。 因隨時間變化 (負）側，所 ，則壓力感應 2 〜10-6Torr 左 S壓漂移v位 使用之狀態， 論何時均可進 多v是否超過 力感應器的輸 要進行壓力感 整，而自動地 細方塊構成圖 幅電路1 7 · 1 8 E由於與第9圖 也與第1 1圖的 直線性修正部 )，而將來自 體溫度修正部 -26- 1235825 (22) 又，在第11圖，41爲D/A變換器、42〜44爲A/D變換 器、7爲控制電路、7c爲比較手段、20爲CPU、7a’爲流量 運算手段中之流量直線性修正部、4 8爲壓力感應器的溫度 漂移修正手段、49爲壓力感應器的時間變化零點漂移修正 手段、50爲壓力升壓電路，藉由來自於該壓力升壓電路50 的輸出，來開關控制控制閥（未圖示）。 壓力感應器輸出的時間變化零點漂移修正手段49是具 備：判定來自於A/D變換器44的輸入値v是否超過設定値 (-0.13%FS = -2.6mV )之手段（感應器輸出判定手段49a ) ;及判定是否朝控制閥9設定著強制關閉的輸入、或壓力 設定訊號V是否爲0.6%FS以下之作動條件判定手段49b， 當藉由作動條件判定手段49b，確認爲①是否朝控制閥9設 定著強制打開②或強制關閉、③壓力設定訊號V是否爲 0.6%FS ( V = 60mV ·感應器輸出電壓 v = 12mV)以下之何者 ，且藉由感應器輸出判定手段49a確認壓力感應器3的輸 出v爲-0.13%FS以上時，自動地由D/A變換器將相當於 + 〇.13%FS的零點調整用電壓（v^2.6mV )輸入至固定增 幅電路1 6的補償端子1 6a，藉此，以相當於壓力感應器的 時間變化零點漂移（-〇.13%FS )之漂移輸出（-2.6mV )被 抵銷，進行自動零點調整。 第1 2圖是本發明之壓力感應器時間變化零點漂移修正 手段49的作動流程圖。在步驟πη，輸入來自於壓力感應 器3的輸出電壓ν，且在步驟m 2輸入對於控制閥9的強制打 開的輸入訊號Vc或強制關閉的輸入訊號Vo。然後，在步 -27- (23) 1235825 驟m3，判定前述v是否超過- 〇.13%FS ( v二-2.6mV ) 步驟m 4，判斷是否存在有V c或V 〇、及壓力設定 是否爲0.6 % F S以下。 最後在步驟m5，當滿足了 V超過-12mV且V Vo > 0或V < 0.6 %FS的任一條件時（步驟m5 )， ，將( =2.6mV )的電壓輸出輸入至固定增幅電 補償端子16a。 再者，在前述第1至1 1圖所示的本發明實施形 據在臨界條件下所使用的壓力式流量控制裝置說明 明，但本發明亦適用於在非臨界條件下所使用的壓 裝置或單獨使用的壓力感應器。 【發明效果】 在申請專利範圍第1項之發明，由於根據藉由 化零點漂移修正手段所判斷的結果，來除去受到隨 化所產生的零點漂移，故能夠大幅地提昇壓力感應 力檢測精度。 在申請專利範圍第2項之發明，藉由根據以時 零點漂移修正手段進行判斷的結果，來將與感應器 時間變化所產生的漂移電壓相同且逆極性的電壓輸 壓力感應器的輸出增幅之增幅器的補償端子，來除 述隨時間變化所產生的零點漂移。其結果，能夠大 昇壓力感應器的壓力檢測精度。 在申請專利範圍第3至8項之發明，由於提昇了 -28- ，又在 訊號V c > ◦或 在步驟 路1 6的 態，根 了本發 力控制 時間變 時間變 器的壓 間變化 的受到 入至將 去因前 幅地提 成爲壓 1235825 (24) 力控制或流量控制的基礎之壓力感應器的壓力檢測精度， 故可大幅地提昇壓力或流量的控制精度。 又在申請專利範圍第9及11項之發明，由於以相當於 以壓力感應器所檢測到的滿標電壓FS控制精度以下例如 滿標壓力FS的0.1 3%之感應器輸出電壓爲基準，進行自動 零點修正，故可將流量測定値經常地保持於預定的精度範 圍內。 且，在申請專利範圍第1 〇及1 2項之發明，由於當設置 孔口上游側的壓力感應器的環境條件是處於接近真空的情 況時，自動地進行時間變化零點漂移的修正，故能夠以更 高精度來進行零點漂移的除去。 在申請專利範圍第13及第14項之發明，由於將漂移修 正用電壓供給至增幅器的補償端子之D/A變換器作成與壓 力感應器的溫度漂移修正手段共用，故能夠將壓力控制裝 置或壓力式流量控制裝置的壓力感應器之溫度漂移或時間 變化漂移的修正手段之結構簡單化。 本發明是如上所述，爲可達到優良的實用效果之發明 【圖式簡單說明】 第1圖是在本發明所使用之半導體元件型壓力感應器 (壓力應變計）之構造圖。 第2圖是顯示在本發明所使用的壓力感應器之安裝狀 況的斷面圖。 -29 - (25) 1235825 第3圖是顯示在本發明所使用的壓力感應器的真空保 持下之零點輸出的隨時間變化之曲線圖。 第4圖是顯示在本發明所使用的壓力感應器的真空保 持下之零點輸出的隨時間變化之「根據吸真空前的使用經 歷之差異」的線圖。 第5圖是顯不以0 ( T 〇 r r、真空）〜6 Ο T 〇 r r的循環使在 本發明所使用的壓力感應器之壓力變化之情況的零點輸出 的隨時間變化之線圖。 第6圖是顯示以0 ( Torr、真空）〜O.IMPaG的循環使 壓力感應器之壓力變化之情況的零點輸出的隨時間變化之 線圖。 第7圖是顯示將壓力感應器的壓力保持於O.IMPaG的 情況時之零點輸出的隨時間變化之線圖。 第8圖是在本發明的實施形態所使用之壓力式流量控 制裝置的構成圖。 第9圖是修正因在本發明的實施形態所使用的壓力式 流量控制裝置的溫度所引起的壓力感應器之輸出變動的手 段中之零點輸出修正部分的方塊構成圖。 第1 0圖是顯示壓力感應器的零點輸出電壓的修正與滿 標（FS )的關係之說明圖。 第1 1圖是本發明之壓力式流量控制裝置的控制電路之 方塊構成圖。 第1 2圖是本發明之壓力感應器之時間變化零點漂移修 正手段的作動流程圖。 -30· (26) 1235825 第1 3圖是顯示以往的壓力式流量控制裝置的一例之圖 第1 4圖是顯示以往的壓力式流量控制裝置的一例之圖 【主要元件符號說明】 P1···孔口上游側氣體壓 A…壓力感應器 φ B…管路 1…壓力式流量控制裝置 . 2…孔口 2a···孑L 口 3…上游側壓力感應器 4…上游側配管 5…下游側配管 6…溫度感應器 φ 7…控制電路 7a…流量運算手段 _ 7b…流量設定手段 _ 7c···比較手段 _ 8…閥驅動部 * 9…控制閥 - 10…氣體供給源 11…壓力調整器 -31 - (27) (27)1235825 12、13·.·閥 14…處理室 15…真空泵 16…固定增幅電路 1 6 a…補償端子In the description of the above-mentioned Figs. 9 and 10 ', the zero output drift v. -2 · 0 m V -23- 1235825 (19) It is caused by the temperature change of fluid (gas). Therefore, 'a' is taken as the temperature characteristic of the pressure sensor output v, and straight line C is taken as the temperature characteristic of the sensor output V. On the other hand, in the present invention, the zero point correction of the time variation of the pressure sensor output v is taken as a problem, so if the ninth and the ninth points are shifted by the output V, then. (That is, the pressure sensor output v with zero pressure. If it is set as the zero output drift due to the change with time, it is the correction method described in Figures 9 and 10 or its relationship with the full scale (FS setting) It can be directly applied to the correction of the zero output due to the change with time. That is, the straight line a of the above-mentioned Fig. 10 is used as the pressure sensor output change characteristic with time, and the straight line C is used as the output change of the amplifier output V. The characteristics can be grasped. In addition, regarding the measurement method of the time-varying characteristics of v of the pressure sensor 3 shown in FIGS. 3 to 6 described above, detailed descriptions thereof are omitted here so that the pressure sensor 3 is assembled as The pressure of the pipeline B in the form shown in Figure 2 is set to zero pressure (vacuum i0_5 ~ 10 ") by the vacuum pump (not shown), which is Pi and 〇 (X 1 0 ″ kPaA). Variation V of the zero output of 3 (drift voltage v.) 'Or the measurement time of the variation of the zero output of the pressure sensor 3 with the pressure in B maintained at an arbitrary setting 者. Figure 3 shows the display stays true An example of zero-point output drift due to time change of pressure device 3 in the case of empty conditions is the change output characteristic diagram, the horizontal axis is time (H r), and the vertical axis is the zero point. The time output of the drift V of the first) is clear, and the 5Torr inductive pipeline within the sensing time passes and the sensing time drifts -24-1235825 (20) shift voltage v. The sensor output voltage 2mV is equivalent to 0.1% of the full-scale FS when the full-scale is taken as lOOTorr. The PT output OmV line is an ideal case showing no drift, and the curve is the zero output drift actually measured. This drift varies depending on the sample of the pressure sensor, but as mentioned earlier, 0.2 to 0.3% FS (v. = 4 to 6 m V) is formed after about 1 hour, and 0.4% is formed after about 6 hours FS (v ^ 8mV) degree. This zero output drift voltage v. It is the compensation terminal 16 a applied to the fixed amplifier circuit 16 of the aforementioned FIG. 9. In the present invention, when the pressure sensor 3 is caused by a zero-point output drift v caused by a time change. When it becomes larger than -0.13% FS (that is, the zero-point output drift v. Is -2.6 m V), the zero-point output drift v. The compensation terminal 16a of the fixed amplifier circuit 16 as shown in Fig. 9 automatically performs the zero adjustment of the pressure sensor 3. In addition, the aforementioned -0.13% FS is used as a reference point for adjusting the zero drift with time. The result of the basic test shown in Figs. 3 to 6 shows that the zero output drift v is maintained under vacuum. It only occurs in the negative direction; and if it has a zero drift of -0.3% FS (Vf2.6mV), it may be within the practical tolerance range of the pressure sensor 3. Specifically, it is first determined whether the output voltage v of the pressure sensor 3 is formed on the negative side. In addition, in the use of the pressure control device, there must be a gas pressure applied to the pressure sensor 3, and the output voltage v of the pressure sensor 3 will not be formed on the negative side. Therefore, if it is determined that the output voltage v of the pressure sensor 3 is on the negative side, it can be seen that the pressure control device is stopped and there is no gas flow -25-1235825 (21). In addition, the zero-point output voltage drift v caused by the pressure sensor 3 is maintained under vacuum. Must appear in-so, if the output drift of the pressure sensor 3 is on the-side, the vacuum degree of the sensor 3 is maintained at or near the vacuum (1〇 \ right). Therefore, if the output of the pressure sensor 3 is identified as the-side, the pressure-type flow control device is in a state where the pressure in the pipeline is kept close to the vacuum, so the adjustment of the zero drift caused by the change with time cannot be performed. . Next, it is determined that the output voltage of the pressure sensor 3 drifts to the aforementioned setting 値 (v = -0.13% FS). Then, if the pressure drift v exceeds the set value, diagnose the zero drift caused by the time change of the adaptor 3 and perform the zero drift V by yourself. Adjustment. Figure 11 shows the details of the control circuit of the pressure control device. The case of the pressure sensor 3, the fixed amplifier circuit 16, the variable amplifier, the A / D converter 19, the compensation D / A converter 40, and the like is the same, and descriptions thereof are omitted. In addition, the control circuit of the pressure type flow control device is almost the same, and a gas temperature correction section is provided only on the output side of the flow rate 7 a ′ in the flow rate calculation means (the temperature detection signal of the temperature sensor 6 is not input here). This point of qi is different from Figure 11. Because the side changes with time (negative), the pressure sensing is 2 to 10-6 Torr. The state of the left S pressure drift v is used. The sensor input is pressure-adjusted, and the picture frame circuit is automatically formed by thin squares (17, 1 and 8E due to the linearity correction part of Fig. 9 and Fig. 11), so it will come from the body temperature correction part. -26- 1235825 (22) In Figure 11, 41 is a D / A converter, 42 to 44 are A / D converters, 7 is a control circuit, 7c is a comparison means, 20 is a CPU, and 7a 'is a flow rate. The flow linearity correction unit in the calculation means, 48 is a temperature drift correction means of the pressure sensor, 49 is a time change zero drift correction means of the pressure sensor, and 50 is a pressure step-up circuit. Output of circuit 50 to open and close the control valve (Not shown). The time-varying zero-point drift correction means 49 of the pressure sensor output is provided with a means for determining whether the input Av from the A / D converter 44 exceeds the setting 値 (-0.13% FS = -2.6mV) (sensor output determination means 49a); and operating condition determination means 49b to determine whether a forced closing input is set to the control valve 9 or whether the pressure setting signal V is 0.6% FS or less, and when the operating condition determination means 49b is used, it is confirmed that ① The valve 9 is set to be forced open ② or forced closed, ③ whether the pressure setting signal V is 0.6% FS (V = 60mV · sensor output voltage v = 12mV), and the pressure sensing is confirmed by the sensor output determination means 49a. When the output v of the converter 3 is -0.13% FS or more, the D / A converter automatically inputs a zero adjustment voltage (v ^ 2.6mV) equivalent to + 0.13% FS to the fixed gain circuit 16 for compensation. Terminal 16a thereby offsets the drift output (-2.6mV) corresponding to the time-varying zero-point drift (-0.13% FS) of the pressure sensor and performs automatic zero-point adjustment. Fig. 12 is a flowchart of the operation of the time-varying zero-point drift correction means 49 of the pressure sensor of the present invention. In step πη, the output voltage ν from the pressure sensor 3 is input, and in step m2, the input signal Vc forcibly opening to the control valve 9 or the input signal Vo forcibly closing is input. Then, in step -27- (23) 1235825 step m3, it is determined whether the aforementioned v exceeds-〇.13% FS (v 二 -2.6mV) step m 4, it is determined whether V c or V 〇 exists, and whether the pressure setting is It is 0.6% FS or less. Finally, in step m5, when V exceeds -12mV and either V Vo > 0 or V < 0.6% FS is satisfied (step m5), the voltage output (= 2.6mV) is input to the fixed amplifier Compensation terminal 16a. In addition, the pressure type flow control device used in the embodiment of the present invention shown in Figs. 1 to 11 described above under critical conditions is explained, but the present invention is also applicable to a pressure device used under non-critical conditions. Or a separate pressure sensor. [Effect of the invention] The invention in item 1 of the scope of patent application, because the zero point drift caused by randomization is removed based on the result determined by the zero point drift correction method, can greatly improve the accuracy of pressure sensing force detection. The invention in item 2 of the scope of patent application, by using the judgment result based on the time-zero drift correction method, increases the output of the pressure sensor with the same polarity as the drift voltage generated by the time change of the sensor and the reverse polarity. Amplifier's compensation terminal to eliminate the zero drift caused by time changes. As a result, the pressure detection accuracy of the pressure sensor can be greatly increased. The inventions in items 3 to 8 of the scope of patent application, because of the increase of -28-, and the signal V c > ◦ or the state of step 16 is based on the pressure of the time control of the time-varying time converter. Due to the change in pressure, the accuracy of the pressure detection of the pressure sensor, which will be the basis of pressure control or flow control, will increase the accuracy of pressure or flow control. The inventions in the 9th and 11th patent applications are based on the sensor output voltage equivalent to 0.1 3% of the full-scale pressure FS below the control accuracy of the full-scale voltage FS detected by the pressure sensor. Automatic zero point correction, so the flow rate measurement can be kept within a predetermined accuracy range. Moreover, in the inventions of the scope of application for patents Nos. 10 and 12, since the time condition for the pressure sensor on the upstream side of the orifice is close to a vacuum, the time change zero point shift is automatically corrected, so it can be corrected. Zero point removal is performed with higher accuracy. In inventions Nos. 13 and 14 of the scope of patent application, since the D / A converter supplying the drift correction voltage to the compensation terminal of the amplifier is shared with the temperature drift correction means of the pressure sensor, the pressure control device can be used. The structure of the correction method for temperature drift or time change drift of the pressure sensor of the pressure type flow control device is simplified. The present invention is an invention which can achieve excellent practical effects as described above. [Brief description of the drawings] FIG. 1 is a structural diagram of a semiconductor element type pressure sensor (pressure strain gauge) used in the present invention. Fig. 2 is a cross-sectional view showing a mounting state of a pressure sensor used in the present invention. -29-(25) 1235825 Fig. 3 is a graph showing the change with time of the zero output under the vacuum hold of the pressure sensor used in the present invention. Fig. 4 is a line chart showing the "time-to-vacuum difference" in the zero-point output of the pressure sensor used in the present invention while maintaining the vacuum. Fig. 5 is a graph showing the time-dependent change of the zero output when the pressure of the pressure sensor used in the present invention is changed in a cycle of 0 (T 0 r r, vacuum) to 6 0 T 0 r r. Fig. 6 is a graph showing the change over time of the zero output when the pressure of the pressure sensor is changed in a cycle of 0 (Torr, vacuum) to 0.1 MPaG. Fig. 7 is a graph showing the change over time of the zero output when the pressure of the pressure sensor is maintained at 0.1 MPaG. Fig. 8 is a configuration diagram of a pressure type flow control device used in an embodiment of the present invention. Fig. 9 is a block diagram of a zero output correction section in a means for correcting a change in output of a pressure sensor due to a temperature of a pressure-type flow control device used in an embodiment of the present invention. Fig. 10 is an explanatory diagram showing the relationship between the correction of the zero output voltage of the pressure sensor and the full scale (FS). Fig. 11 is a block diagram of a control circuit of a pressure type flow control device of the present invention. Fig. 12 is a flow chart of operation of the time-varying zero-point drift correction method of the pressure sensor of the present invention. -30 · (26) 1235825 Fig. 13 is a diagram showing an example of a conventional pressure type flow control device. Fig. 14 is a diagram showing an example of a conventional pressure type flow control device. [Description of main component symbols] P1 ·· · Gas pressure on the upstream side of the orifice A ... Pressure sensor φ B ... Pipeline 1 ... Pressure-type flow control device. 2 ... Orifice 2a ... · L port 3 ... Pressure sensor 4 on the upstream side ... Piping 5 on the upstream side ... Downstream piping 6 ... Temperature sensor φ7 ... Control circuit 7a ... Flow rate calculation means_7b ... Flow rate setting means_7c ... Comparative means_8 ... Valve drive unit * 9 ... Control valve-10 ... Gas supply source 11 ... Pressure regulator -31-(27) (27) 1235825 12, 13 ... Valve 14 ... Processing chamber 15 ... Vacuum pump 16 ... Fixed amplifier circuit 1 6a ... Compensation terminal
17、18···可變增幅電路 19…A/D變換器 20··· CPU 2 1…感應器座 22…感應器晶片 23…隔膜 2 4…隔膜座 25…矽油 26…封裝體 27…導銷 28…安裝主體 29…按壓螺帽 3 0…軸承 31…密封環 40…補償用D/A變換器 40a、40b…D/A變換器 40c、4 0d…緩衝器 40e…合成用緩衝器 4 1…D / A變換器 (28) (28)1235825 42、43、44··_ A/D 變換器 7a’…流量運算手段中之流量直線性修正部 48…壓力感應器之溫度漂移修正手段 49…壓力感應器之時間變化零點漂移修正手段 49a···感應器輸出判定手段 49b…作動條件判定手段 50…壓力升壓電路17, 18 ... Variable Amplifier Circuit 19 ... A / D Converter 20 ... CPU 2 1 ... Sensor Block 22 ... Sensor Chip 23 ... Diaphragm 2 4 ... Diaphragm Block 25 ... Silicone Oil 26 ... Package 27 ... Guide pin 28 ... Mounting body 29 ... Press nut 3 0 ... Bearing 31 ... Sealing ring 40 ... D / A converters 40a, 40b for compensation ... D / A converters 40c, 4 0d ... Buffer 40e ... Composite buffer 4 1 ... D / A converter (28) (28) 1235825 42, 43, 44 ... A / D converter 7a '... Flow linearity correction unit in flow calculation means 48 ... Temperature drift correction of pressure sensor Means 49 ... Time change zero drift correction means 49a of the pressure sensor ... Sensor output determination means 49b ... Operating condition determination means 50 ... Pressure booster circuit
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